Furnace retorts



F. J. BORON FURNACE RETORTS July 21, 1964 2 Sheets-Sheet 1 Filed Dec. 21, 1961 INVENTOR. FRAN K J. BORON ATTORNEYS July 21, 1964 F. J. BORON 3,141,658

FURNACE RETORTS Filed Dec- 21, 1961 2 Sheets-Sheet 2 W3 W4 FIG- 3A INVENTOR. FRAN K J. BO RON ATTORNEYS United States Patent 3,141,658 FURNACE RETORTS Frank J. Boron, Elyria, Ohio, assignor to American Brake Shoe Company, New York, N.Y., a corporation of Delaware Filed Dec. 21, 1961, Ser. No. 161,190 2 Claims. ((1263-47) This invention relates to furnace retorts, and in particular those of the mufile type.

A well-known form of retort construction is represented by a relatively large single piece casting that is substantially symmetrical between the ends from the standpoint of outward appearance at least. The retort is rotatable, and the internal construction includes integrally cast projections in the form of ribs or the like. These ribs are confined to the central section of the retort to induce tumbling action on the work charged into the retort.

Retorts of the kind contemplated by the present invention serve a mufiie function in separating the hot gas used for combustion from a special gas atmosphere surrounding the work or charge. Thus, the retort of the present invention includes a heated chamber filled with a gas affording a special atmosphere for the charge. Resultantly, a hot, corrosive, and highly carburizing atmosphere is present which can produce a relatively short life for the retort. This condition could be alleviated by resorting to a heat-resistant alloy, but it is a well-known fact that alloys of this kind are employed most advantageously in connection with centrifugal casting since this results in an exceptionally sound internal structure which justifies the initial high cost of a heat-resistant alloy.

The primary object of the present invention is, therefore, to enable a retort-type furnace to be constructed inclusive of a centrifugally cast center section of heatresistant alloy, but which nevertheless includes the aforesaid projections for inducing a tumbling action on the work charged into the retort. Specifically, it is an object of the present invention to permit such construction to be attained by casting the center section centrifugally as a separate element and thereafter securing separately fabricated ribs in place by welding the same in the desired relationship to the inside of the center section.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment of the present invention and the principle thereof and what is now considered to be the best mode contemplated for applying that principle. Other embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a sectional view of a retort constructed in accordance with the present invention, being taken on the line 1-1 of FIG. 1;

FIG. 2 is a sectional view on the line 22 of FIG. 1;

FIG. 3 is a fragmentary sectional view on an enlarged scale illustrating the details of the manner in which the ribs are welded in place, being taken on the line 3--3 of FIG. 1; and

FIG. 3A is a sectional view of a rib prior to welding the same in place.

The retort heating chamber of the present invention is illustrated in cross-section in FIG. 1. For the most part, the retort is symmetrical from one end to the other and includes a centrifugally cast center section 12 of relatively large diameter, and of uniform geometry and cross-section throughout. This retort will separate the charge contained therein from the hot combustion gas. In accordance with the present invention, sand castings 13 and 14 representing separately fabricated end parts are secured by respective annular welds W1 and W2 to the opposite ends of center section 12. The sand castings 13 and 14 are generally bell-shaped in cross-section, each being inclusive of a cylinder-like end sleeve and an enlarged conical-shaped part the base of which is welded to the related end of the center tube 12.

The center section 12 is where the charge is subjected to the most severe heat, and the action of the hot special atmosphere gas therein. Any crack here renders the retort inoperable, since it is then open to the ambient atmosphere, resulting in oxidation of the work or charge in the retort.

The supporting structure associated with the retort is not shown, but it may be mentioned that one end, such as 13 is the so-called plug end whereat a special atmosphere gas is introduced to be contained in the center section 12. The opposite end section 14 is the discharge end of the retort 10. In operation, the retort 10 is inclined at an angle of approximately 60.

The center section 12 is cast centrifugally of a ferrous heat-resistant alloy such as:

Cr Ni 0 Mn Si e E L 2 1. 25 2.00 Balance 25 68 65 max. max.

Resultantly, the life of the cylindrical part 12 of the retort is prolonged due to the nature of the heat-resistant alloy used therein and the soundness of the casting 12 which is an inherent attribute of a centrifugal casting. Such is made possible under the present invention not only by providing the end sections 13 and 14 as separate sand castings to be welded to the center section asnoted above, but also by separately fabricating and welding in place to the inside of the center section the necessary number of ribs 20 which, when the retort is rotated, assure an effective tumbling action on the charge contained within the center section 12.

The ribs 20, as shown particularly in FIG. 1, are tilted uniformly relative to the longitudinal axis of the shell portion 12 of the retort, and advantageously the angle relative to this axis is approximately 15.

The ribs 20 are preferably cast of the same alloy described above as that selected for the shell or tube section 12 as well as for the end stationarily cast end sections 13 and 14.

As shown in detail in FIG. 3A, each rib 20 includes a flat outer face 20A and substantially straight parallel side surfaces 20B and 20C. The sides 20B and 200 are each necked down in a quarter-round fashion proceeding inwardly from the outer faces thereof, and at a point below the face 20A, to produce a relatively narrow elongated web portion 20W.

The purpose of this is to permit each rib to be secured to the shell 12 by welds W3 and W4 that fill the quarterround indentations of each rib 20 on opposite sides of the web portion 20W. In fact, as will be apparent from FIG. 3, the welds penetrate and melt the web 20W of each rib 20.

In this manner, excellent penetration of the weld material W3 and W4 is assured, thereby serving to firmly lock the ribs 20 in place in the intended geometrical arrangement within the inside diameter of the center section 12 of the retort. This also makes it possible, as noted above, to cast the center part 12 centrifugally.

Hence, while I have illustrated and described a preferred embodiment of my invention, it is to be understood that this is capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a retort, a heating chamber comprising, first, a relatively large hollow cylinder of substantially uniform cross-sectional geometry and uniform thickness throughout, said hollow cylinder being cast centrifugally from a heat resistant ferrous metal alloy to have a prolonged life under severe high temperature conditions; secondly, a pair of separate cast end members, each of said members having a cylindrical end sleeve integral with the smaller end of an enlarged conical part welded at the larger end of said conical part to the ends of said cylinder; and thirdly, a plurality of separately fabricated ribs of a heat-resistant alloy welded to the inside diameter of said cylinder and at an angle relative to the longitudinal axis of said cylinder; the foregoing arrangement enabling the retort to have the center part only, most severely exposed to high temperature conditions, cast centrifugally from a heatresistant alloy capable of having Welded thereto the separately fabricated ribs.

2. A retort heating chamber according to claim 1 wherein the ribs are substantially of undercut form having an apex pointed to the inside surface of said cylinder to present undercut surfaces of the rib outward of the apex, with weldments applied to the surfaces of the rib adjacent the apex to fill said undercut surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 2,135,934 Blasier Nov. 8, 1938 2,739,801 Rankine Mar. 27, 1956 2,829,878 Warrington et al Apr. 8, 1958 2,857,684 Halldorsson Oct. 28, 1958 OTHER REFERENCES Page 1540 of Welding Handbook 1942 edition. Published by the American Welding Society, 33 West Thirty- Ninth Street, New York, New York. 

1. IN A RETORT, A HEATING CHAMBER COMPRISING, FIRST A RELATIVELY LARGE HOLLOW CYLINDER OF A SUBSTANTIALLY UNIFORM CROSS-SECTIONAL GEOMETRY AND UNIFORM THICKNESS THROUGHOUT, SAID HOLLOW CYLINDER BEING CAST CENTRIFUGALLY FROM A HEAT RESISTANT FERROUS METAL ALLOY TO HAVE A PROLONGED LIFE UNDER SEVERE HIGH TEMPERATURE CONDITIONS; SECONDLY, A PAIR OF SEPARATE CAST END MEMBERS, EACH OF SAID MEMBERS HAVING A CYLINDRICAL END SLEEVE INTEGRAL WITH THE SMALLER END OF AN ENLARGED CONICAL PART WELDED AT THE LARGER END OF SAID CONICAL PART TO THE ENDS OF SAID CYLINDER, AND THIRDLY, A PLURALITY OF SEPARATELY FABRICATED RIBS OF A HEAT-RESISTANT ALLOY WELDED TO THE INSIDE DIAMETER OF SAID CYLINDER AND AT AN ANGLE RELATIVE TO THE LONGITUDINAL AXIS OF SAID CYLINDER; THE FOREGOING ARRANGEMENT ENABLING THE RETORT TO HAVE THE CENTER PART ONLY, MOST SEVERELY EXPOSED TO HIGH TEMPERATURE CONDITIONS, CAST CENTRIFUGALLY FROM A HEATRESISTANT ALLOY CAPABLE OF HAVING WELDED THERETO THE SEPARATELY FABRICATED RIBS. 